Outside money is pouring into San Joaquin Valley congressional races, a potentially mixed blessing for candidates and a sure sign of more to come.

Out-of-state donors, in particular, enabled Democrat Amanda Renteria to nearly match the recent fund raising of Rep. David Valadao, R-Hanford, since January. Renteria this week reported raising a total of $303,468 in the first three months of the year, while Valadao reported raising $322,358.

Most of Renteria’s funds came from donors living outside of California.

Particularly for a first-time challenger, posting competitive totals like these can demonstrate political viability. This, in turn, can draw in more money for all sides as campaign professionals sense a real race shaping up.

Renteria reports having $423,965 on hand as of March 31, while Valadao reports having $852,084.

“Central Valley voters are supporting Amanda because they know she can win, because they know the Valley can do better than . . . Valadao, and because everyone is concerned that he’s failed to deliver on immigration reform and improving the lives of our families.,” Renteria’s campaign manager, Emily Nowlin, said Thursday.

Fresno resident John Hernandez is also running, albeit with little money so far, in the 21st Congressional District. The district includes all of Kings County and portions of Fresno, Tulare and Kern counties. As yet, Hernandez has not reported any political contributions.

In the other Valley race that’s captivating the national political parties, Rep. Jeff Denham, R-Turlock, reports having $1.5 million on hand, while Democrat Michael Eggman reports having $426,665. Like Renteria, Eggman is relying so far on out-of-district donors.

By contrast, none of the Republicans seeking to challenge Rep. Jim Costa, D-Fresno, in a district that includes all or portions of Merced, Madera and Fresno counties, have more than $12,000 on hand. Costa reports having $642,539 available.

For challengers and incumbents alike, non-local political donations can yield vulnerabilities as well as the obvious benefits.

Republicans, for instance, are trying to fit Renteria’s out-of-district financial support into a larger narrative that the Capitol Hill veteran and graduate of Stanford and Harvard Business School is a “Washington, D.C., insider.” A GOP tally released Thursday showed less than 1 percent of Renteria’s itemized individual contributions came from district residents.

“If there was any doubt that Amanda Renteria is Washington’s pick for this congressional seat, look no further than the shockingly little support she’s received from the community she’s seeking to represent,” National Republican Congressional Committee spokesman Tyler Q. Houlton said Thursday.

Renteria, a native of the Tulare County town of Woodlake and a graduate of the town’s high school, moved back to the Valley last August.

Democrats, in turn, cite Valadao’s out-of-district donors amid their own preferred attack lines. Democrats note, for instance, that the political action committee for the Kansas-based Koch Industries, whose political largesse has made it a frequent Democratic target, has now contributed $7,500 to Valadao.

“It’s not surprising to see shady out-of-state billionaires padding the campaign coffers of Congressman Valadao,” Democratic Congressional Campaign Committee spokesman Tyrone Gayle said in an email Thursday, further asserting that Valadao’s alleged support for “the ultra-wealthy like the Koch Brothers was the clearest sign that he has the wrong priorities.”

In a statement Thursday, the Valadao campaign countered that “Rep. Valadao is proud of the broad support for his reelection” and added that “these funds will be used to respond to attacks from the liberal and radical environmental groups that are fully funding our opponent’s campaign.”

Denham was publicly criticized this week by Stanislaus County Republican Central Committee member Marty Miknus for accepting a $10,000 contribution from the Santa Ynez Band of Chumash Indians. The Dec. 2 contribution from the Santa Barbara County based tribe to the Denham Victory Fund came after Denham backed a land-transfer bill sought by the tribe.

Denham has long raised money from tribes, with four other out-of-district tribes contributing to his campaign so far this year. The casino-operating Santa Ynez tribe, in turn, spreads its checks across state and party lines. At least seven other lawmakers who co-sponsored the tribe’s land-transfer legislation have, like Denham, received Santa Ynez contributions since last summer, records show.

Neither Denham nor his spokesperson could be reached to comment Thursday.